Flue Gas Desulphurisation withSIMONA®PP-H 100 AlphaPlus Pipes

Project Report 17

2 SIMONA Project Report 17 05/2006

Project Data

Project Renewal of the Flue Gas Desulphurisation Plant (FGDP) at Niederaussem Power

Station with blast lances made of SIMONA®PP-H 100 AlphaPlus

Requirements Chemical and abrasive stress externally and internally

Medium: HCl, SO2, HF, milk of lime-gypsum suspension, pH 3–4

Solids content: approx. 12 %–15 % service pressure: approx. 0.5 bar

Service temperature: approx. 70 °C

Client RWE Energie AG, Niederaussem Power Station

Installed power: 3864 MW in

9 blocks, lignite demand: 21.2 mill. t/a

General contractor K & W Knäpper & Witt GmbH, Nordkirchen-Capelle

Subcontractor ATEA GmbH, Ransbach-Baumbach

Plastic construction KTW GmbH & Co. KG, Ransbach-Baumbach

Project management ATEA GmbH, Ransbach-Baumbach

Assembly

Technical support Applications Technology Dept., SIMONA AG, 55606 Kirn

Connection systems Heated tool butt welding in accordance with DVS 2207-11

Extrusion welding in accordance with DVS 2207-4

Hot-gas string bead welding in accordance with DVS 2207

Socket connections on site with lip seals

Products used SIMONA®PP-H 100 AlphaPlus pipes, d 110 – d 500, SDR 11, length = 5 m

SIMONA®PP-H 100 AlphaPlus fittings: tees, reducers, flanges

SIMONA®PP-DWU sheets

Time 2004

05/2006 Project Report 17 SIMONA 3

SIMONA®PP-H AlphaPlus – a Cost-effective Solution forFlue Gas Desulphurisation Plants

Owing to the high load of combustion gases on the flue-

gas desulphurisation plant in Niederaussem, RWE

Energie AG decided on renovation. On account of cor-

rosion the rubber-lined steel pipes generally have a ser-

vice life of 5 to 8 years.

For this reason a search was conducted for material

which would be able to replace the rubber-lined steel

pipes previously used as blast lances. The new materi-

al would have to have a longer service life and ensure

a high degree of operational reliability, and thus reduce

running costs. Therefore RWE Energie AG decided in

favour of SIMONA® PP-H 100 AlphaPlus – a material

which meets all the criteria.

The flue gas desulphurisation plants (FGDP) remove

acid and aggressive pollutants such as HCl, SO2 and

HF gases from the combustion gases of the power

station using a pH-controlled scrubbing liquid. The

scrubbing liquid for the flue gas desulphurisation

plants consists of dissolved and undissolved lime as

well as gypsum components which arise from chemi-

cal absorption of the lime with SO2 pollutants. In lignite

power stations the scrubbing liquid has a temperature

approx. 70 °C and a pH between 3 and 4. Owing to the

acid potential and the moist atmosphere at increased

temperature steel components must be protected

against corrosion very effectively. On account of the

gypsum-milk of lime suspension the pipelines are also

subjected to abrasion.

When the lignite power stations were upgraded with

flue gas scrubbers in 1987 to 1988, various grades of

soft rubber were used to line the scrubbing towers

made of black steel and for the suspension-carrying

pipes.

1

1: Flue gas desulphurisation plant in Niederaussem 2: Flue after repairs

2

4 SIMONA Project Report 17 05/2006

The good mechanical properties also qualified

SIMONA®PP-H 100 AlphaPlus as an ideal structural

material. In a short-time tensile test high moduli of

elasticity were measured up to a temperature of

100 °C (see Fig. 1).

The material SIMONA®PP-H 100 AlphaPlus has very

good chemical resistance to organic and inorganic

acids, alkalis and solvents up to temperatures of

100 °C. The media occurring in the absorption

scrubbers, such as hydrochloric acid and sulphuric

acid, have no influence on the service capability of

SIMONA®PP-H 100 AlphaPlus for many years. That is

why from a chemical aspect long service lives are to

be expected. For many decades PP-H 100 has been

successfully used in the chemical industry and in

pickling and regenerating systems for precisely that

reason. As a result, in many sectors PP-H 100 has

replaced metal materials, which often have very short

service lives owing to increased corrosion. SIMCHEM

5.0, our CD-ROM catalogue for chemical resistance

offers detailed information on the corrosion resis-

tance of SIMONA®products.

The high abrasion resistance of SIMONA® PP-H 100

AlphaPlus was demonstrated in various laboratory

tests and practical experiments. For example, in a

sand-slurry test the indoor wear of pipes was simu-

lated and a high wear resistance was demonstrated in

comparison with other materials. In addition, in a

spray test, which simulates outdoor wear, the high

wear resistance of PP-H 100 to erosion was measured

by spraying the surface with an abrasive liquid (see

Fig. 2).

The rubber linings have to be renewed every 5 to 8

years owing to the loads. This means considerable

expenditure and increased down times. In searching

for alternatives the main focus of attention was on

operational reliability and longer service lives, in order

to reduce running costs.

SIMONA®PP-H 100 AlphaPlus – an ideal structural

material

When stainless steels, GRP (glass-fibre reinforced

plastic) and modified GRP surfaces and SIMONA®

PP-H 100 AlphaPlus had been examined for service

capability in extensive tests, SIMONA®PP-H 100

AlphaPlus proved to be the most cost-effective mate-

rial with the desirable longer service life. In addition,

SIMONA®PP-H 100 AlphaPlus has excellent chemical

resistance, a high level of physical stability of up to

100 °C, high abrasion resistance and reduced flow

resistance.

20 °C 40 °C 60 °C 80 °C 100 °C

2000

1500

1000

500

0

MPa

Fig. 1: Modulus of elasticity in traction of SIMONA®PP-H100 AlphaPlus measured an a pressed sheet

3 4

05/2006 Project Report 17 SIMONA 5

3: Blast lance components made of SIMONA®PP-H 100AlphaPlus

4: Extrusion welds on the branches for the nozzles5: Lifting of a prefabricated nozzle lance6: Assembled nozzle level

Advantages confirmed in empirical test

Suspension-carrying PP-H 100 liner pipes confirmed

the excellent laboratory results in a two-year test at a

power station. It was also demonstrated that owing to

the use of plastic pipes a higher level of cost-effective-

ness is achieved compared with rubber-lined steel

pipes. Owing to the very low surface roughness Ra of

SIMONA®PP-H 100 AlphaPlus pipes amounting to less

than 0.4 µm the flow resistance, and hence pressure

loss, is reduced by up to 10 per cent depending on the

velocity of flow.

The actual starting position at Niederaussem lignite

power station

The lignite power station operated by RWE Energie AG in

Niederaussem has a capacity of 3864 MW. Of that figure

1,000 MW are generated at an efficiency of over 43 % in

a plant (BoA I) which was commissioned in 2002. The

old plants operate at an efficiency of more than 31 %.

The combustion flue gases are cleaned in special

scrubbers using appropriate wet processes. Desulphu-

risation is performed using milk of lime, which is

sprayed in a fine current of mist flowing counter to the

flue gas. Tapered nozzles made of silicon carbide (SiC),

which are attached to the branches of the blast

lances, generate the spray. The reaction product

occurring is gypsum, which, in the purity produced

here, is ideal for the construction industry.

In Niederaussem the old flue gas desulphurisation

plants had to be completely renovated owing to the

long service life. Consequently, the steel scrubbers

with a diameter of approx. 20 m and a height of

approx. 40 m were relined inside and the blast pipes

made of rubber-lined steel (St37) were completely

replaced by SIMONA®PP-H 100 AlphaPlus blast pipes.

The number of nozzle levels was reduced from five to

four because this was acceptable in terms of process

engineering.

Rubb

er

8

7

6

5

4

3

2

1

0

SIMON

A®

PP-H

100

Alph

aPlus

PP-R

80

PE-80

VE-G

F

(55 %

Fibr

e)

VE-G

F-gef

.

(55 %

Fibr

e)St

eel

Fig. 2: � Sand-slurry test (indoor wear) � Short-time spray test (outdoor wear)

65

6 SIMONA Project Report 17 05/2006

Manufacturing the blast lances

The blast lances are made from pipes with graduated

diameters. As a result, the nozzles can be subjected

to virtually constant pressure over the entire length of

the pipes. The largest diameter is 500 mm outside

and the smallest diameter is 110 mm. Diameter is

reduced in up to four stages.

The reducers and nozzle connection pipes are posi-

tioned below the lance so that complete emptying

takes place on shutdown. In addition, the reducers are

arranged off-centre so that flow resistance is reduced

at the bottom and turbulence is avoided. The pipes

and interconnecting sockets were connected to one

another by heated tool butt welding (Fig. 4).

Welding of the branches to the main pipe was conduc-

ted by extrusion welding. The fixed flange and the pipe

segments were also connected to one another by

heated tool butt welding.

In order to absorb the heavy weight of the tapered

nozzles amounting to about 7 kg a sheet 20 mm thick

was welded between two opposite branches. This

ensures that the nozzles always retain their position,

even at a temperature of 70 °C. There have already

been positive experiences with this design for several

years. In order to increase service lives in the light of

abrasion, all the welding flash and edge projections

inside the pipes were removed or levelled. Conse-

quently, turbulence behind the welding flash or edges

is prevented, which might lead to increased erosion at

a flow velocity of 2–3 m/s.

Assembly of the blast lances on site

The blast lance parts delivered were introduced to the

tank through a manhole near the bottom. The nozzle

levels above a height of 28 m were completely clad,

with the exception of an opening through which the

pipe parts were hoisted to the various working levels

using a block and tackle.

The pipes were supported by the existing steel

girders, which had been fitted at intervals of 2 m

(Fig. 6). The pipes were sized so that the bowing of the

pipes is negligible when exposed to a temperature of

70 °C and completely filled with a milk of lime-gypsum

suspension. The pipes with a diameter of 500 mm

were therefore sized with a wall thickness of > 45 mm.

Where bowing was expected to be higher, axial rein-

forcements were provided.

The blast lances were firmly connected to the supply

pipes by means of flange assemblies. They lie on

steel girders and can move freely in an axial direction.

To support the pipes special channels were made

using SIMONA®PP-DWU sheets, which were attached

to the I-beams with PP bolts (Fig. 8). They ensure that

the pipes can move in an axial direction. This move-

ment is chiefly caused by thermal expansion, which is

approximately twelve times greater than that of steel.

At the ends of the blast pipes there are sliding

bearings in order to prevent stresses and strains from

building up on account of thermal expansion by the

pipes.

7 8

7 8

05/2006 Project Report 17 SIMONA 7

The individual pipes prefabricated at the workshop

were connected to one another using special inter-

connecting sockets. To make sure the socket connec-

tions remain tight even in the event of tensile loads

and do not become detached during vibrations, they

were secured with safety bolts to prevent axial forces

(Fig. 9).

After an installation period of about two weeks all the

scaffolding was removed. Then the mist collectors

made of SIMONA®PP-DWU sheets were fitted above

the nozzle levels. Finally, the scrubber was put into

service again, so cleaned flue gases were able to

leave the chimney again after only three weeks.

Literature

Dr. Boris Gibbesch:

Practical Experiences of Plastic Pipes in Flue Gas

Desulphurisation Plants; specialist conference

”Corrosion Protection in Flue Gas

Desulphurisation Plants“ in Essen, 1997

Dr. B. Gibbesch, M. Schütz, St. Müller:

Use of PP/GRP composite structures in

suspension-carrying pipes of a flue gas

desulphurisation plant, VGB Kraftwerkstechnik

6/98, P. 103–111

7: During installation of the pipes at one level:the various pipe segments were sized so that it wouldbe possible to have them assembled by four persons

8: Channel support made of SIMONA®PP-DWU sheets9: Sliding bearing at the end of the blast lance in order to

absorb thermal expansion10: View of the nozzle levels from below, revealing the size

of the scrubbing towers

9 10

Pipes, fittings, valves

Available ex stock

PP-H 100 AlphaPlus polypropylene, homopolymer, grey RAL 7032

Properties

� High impact resistance

� High chemical resistance (excellent in contact with many acids,

alkalis and solvents)

� Maximum tension crack resistance

� Corrosion resistance

� Good hydraulic properties due to smooth interior pipe surfaces

(no deposits)

� Physiological safety

8 SIMONA Project Report 17 05/2006

Range of Products

SIMONA AG is one of the leading

manufacturers of thermoplastic

semi-finished products in the

world. Over 40 years of experi-

ence in formulation, production

and processing qualify us as

specialists with unique know-

how. This experience and close

contact with our customers

ensure high-quality products and

superior customised solutions.

PP-H

100

Alph

aPlus

Pipes, fittings, valves

Pressure pipes �

Ventilation ducts �

Fittings for IR/butt welding �

Fittings for electrofusion welding �

Special fittings �

Fittings for flange assemblies �

Valves �

For production reasons individual sizes of injection-moulded fittings are also manufactured inPP-R 80.

Semi-finished Products

Standard articles

PP-DWU Homopolymer, permanent-heat resistant, grey

PP-DWU-SK Homopolymer, permanent-heat resistant, grey, polyester-backed

Available on request

PP-DWU-B Homopolymer, permanent-heat resistant, grey, for tanks requiring

mandatory test certificates

PP-DWU-GK Homopolymer, permanent-heat resistant, grey, glass fibre-backed

05/2006 Project Report 17 SIMONA 9

Properties

� High chemical resistance (excellent in contact with many acids, alkalis

and solvents)

� Permanent-heat resistance

� Corrosion resistance

� Excellent processing capability

� Physiological safety

PP-D

WU

DWU-

B

PP-D

WU-

SK

PP-D

WU-

GK

For further information

about application issues

please contact our

Applications Technology

Department:

Tel.: +49 (0) 67 52/14-393

ata@simona.de

Brochures and

catalogues containing

further information

� Semi-finished Products

Catalogue

� Pipes and Fittings

Brochure

� SIMPLAST 1.0

� SIMCAT 3.1

� SIMCHEM 3.0

� Semi-finished Products

for Tank/Vessel

Construction Brochure

For an overview and to order

further brochures visit our

website, or give us a call:

Marketing

Tel.: +49 (0) 67 52/14-383

marketing@simona.de

www.simona.de

Semi-finished products

Extruded sheets � � � �

Pressed sheets � �

Welding rods � �

Solid rods � �

Profiles

� Standard articles � Available on request

10 SIMONA Project Report 17 05/2006

Well-advised from Start to Finish

For you in the field of chemical

apparatus and installation engine-

ering this means:

� Advice concerning the chemi-

cal resistance of SIMONA®

materials.

� Exposure tests in accordance

with DIN 16888 Parts 1–2

and ISO 4433 Parts 1–4

� Appraisal of reduction factors

by means of immersion tests

or determination by internal

pressure creep rupture

strength tests

� Testing of the potential of a

liquid for initiation of tension

cracks

� Assessment of permeation

during use in composite con-

struction and in lining tech-

nology with an appropriate

material recommendation

For tank/vessel construction we

offer you the following services:

� Appraisals and verifiable

structural analyses for rec-

tangular tanks (perimeter

reinforcements, cross-ribbed)

and circular tanks in accor-

dance with DVS 2205

� Design consulting

� Processing instructions

� Structural analyses of shafts

� Theoretical and practical

training sessions

Take advantage of our expertise

in finding the optimum product

to suit your project. We offer you

a comprehensive advisory service

provided by staff from our Appli-

cations Technology Department

and the sales organisation.

From the planning of your project

through to pre-engineering in the

field. Worldwide.

In the field of composite

construction and lining we can

advise you on:

� Lining technology

� Welding processes

� Selection of fabric material

� Gluing technique or selection

of reaction resin

� Surface pretreatment

� Composite construction

Other services offered

� Training for your members

of staff in the field or at our

Technology Centre in Kirn

� Customised affixing of

sheets

SIMONA Advisory Service

Tel.: +49 (0) 6752/14-393

Fax: +49 (0) 6752/14-302

ata@simona.de

All information provided in this brochure is based on the state of the art and has been compiled to the best of our knowledge.

All dimensions and weights are theoretical figures and are subject to the normal productiontolerances. Subject to change without notice, also with regard to dimensions, weights anddesign.

Colours shown are dependent on the printing process. To match colours accurately we recommend you request original colour samples.

K+

D 0

5/0

6 -

1300 -

John

en

We look forward to assisting you

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